The cutting tool disclosed in Patent Document 1 is known as a conventional cutting tool. Patent Document 1 discloses a cutting tool for forming a groove in an end surface of a workpiece. Such cutting tool comprises a plate member. A plate member is used to appropriately adjust the amount of projection of an edge part in accordance with the depth of a groove to be machined. Such plate member is curved as seen from a leading end side and is fixed to a tool block by means of a clamping member. When using such cutting tool, it is general to eject, from a hose, etc., coolant for cooling an edge part and to supply the coolant to the edge part.